Add remote verify script

README.md

@@ -27,8 +27,11 @@ Each local snapshot is named `move-YYYYMMDD-HHMMSS`.
 - Run the script as an account that can use `zfs` on the source server.
 - The source host needs Bash, ZFS utilities, and SSH.
 - The destination host needs ZFS utilities and the destination pool must exist.
+- Both hosts need `rsync` to run the verification script.
 - The SSH account on the destination must be able to execute `sudo -n zfs`
   without a password prompt.
+- For verification, that account must also be allowed to run `sudo -n rsync`
+  without a password prompt.
 - SSH must use a private key or SSH agent. Password authentication is disabled
   by the script so a migration cannot pause and prompt once per dataset.
 - SSH connectivity and host-key verification must already work.
@@ -48,6 +51,16 @@ Example:
 bash zfs-move-over-ssh.sh tank root@new-server backup/tank
 ```
 
+Verify the resulting filesystems after mounting them on both hosts:
+
+```bash
+bash zfs-verify-over-ssh.sh tank root@new-server backup/tank
+```
+
+The verifier maps datasets using the same relative paths as the move script.
+It uses a read-only `rsync --dry-run --checksum` comparison and exits with
+status `1` when it finds missing, extra, changed, or metadata-different files.
+
 Use a non-standard SSH key or port when needed:
 
 ```bash
@@ -139,10 +152,13 @@ Options:
   bash zfs-move-over-ssh.sh tank admin@new-server backup/tank
    ```
 
-5. Verify the received datasets and data before retiring the source:
+5. Mount the received datasets, then verify their data before retiring the
+  source. `zfs-move-over-ssh.sh` receives with `-u`, so the destination filesystems
+  are unmounted until you explicitly mount them:
 
    ```bash
-  ssh admin@new-server 'sudo zfs list -r backup/tank'
+  ssh admin@new-server 'sudo zfs mount -a'
+  bash zfs-verify-over-ssh.sh tank admin@new-server backup/tank
    ```
 
 ## Safety and Recovery